/*
 * Event loop based on Windows events and WaitForMultipleObjects
 * Copyright (c) 2002-2006, Jouni Malinen <j@w1.fi>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * Alternatively, this software may be distributed under the terms of BSD
 * license.
 *
 * See README and COPYING for more details.
 */

#include "includes.h"
#include <winsock2.h>

#include "common.h"
#include "eloop.h"


struct eloop_sock {
    int sock;
    void *eloop_data;
    void *user_data;
    eloop_sock_handler handler;
    WSAEVENT event;
};

struct eloop_event {
    void *eloop_data;
    void *user_data;
    eloop_event_handler handler;
    HANDLE event;
};

struct eloop_timeout {
    struct os_time time;
    void *eloop_data;
    void *user_data;
    eloop_timeout_handler handler;
    struct eloop_timeout *next;
};

struct eloop_signal {
    int sig;
    void *user_data;
    eloop_signal_handler handler;
    int signaled;
};

struct eloop_data {
    int max_sock;
    size_t reader_count;
    struct eloop_sock *readers;

    size_t event_count;
    struct eloop_event *events;

    struct eloop_timeout *timeout;

    int signal_count;
    struct eloop_signal *signals;
    int signaled;
    int pending_terminate;

    int terminate;
    int reader_table_changed;

    struct eloop_signal term_signal;
    HANDLE term_event;

    HANDLE *handles;
    size_t num_handles;
};

static struct eloop_data eloop;


int eloop_init(void)
{
    os_memset(&eloop, 0, sizeof(eloop));
    eloop.num_handles = 1;
    eloop.handles = os_malloc(eloop.num_handles *
            sizeof(eloop.handles[0]));
    if (eloop.handles == NULL)
        return -1;

    eloop.term_event = CreateEvent(NULL, FALSE, FALSE, NULL);
    if (eloop.term_event == NULL) {
        printf("CreateEvent() failed: %d\n",
                (int) GetLastError());
        os_free(eloop.handles);
        return -1;
    }

    return 0;
}


static int eloop_prepare_handles(void)
{
    HANDLE *n;

    if (eloop.num_handles > eloop.reader_count + eloop.event_count + 8)
        return 0;
    n = os_realloc(eloop.handles,
            eloop.num_handles * 2 * sizeof(eloop.handles[0]));
    if (n == NULL)
        return -1;
    eloop.handles = n;
    eloop.num_handles *= 2;
    return 0;
}


int eloop_register_read_sock(int sock, eloop_sock_handler handler,
        void *eloop_data, void *user_data)
{
    WSAEVENT event;
    struct eloop_sock *tmp;

    if (eloop_prepare_handles())
        return -1;

    event = WSACreateEvent();
    if (event == WSA_INVALID_EVENT) {
        printf("WSACreateEvent() failed: %d\n", WSAGetLastError());
        return -1;
    }

    if (WSAEventSelect(sock, event, FD_READ)) {
        printf("WSAEventSelect() failed: %d\n", WSAGetLastError());
        WSACloseEvent(event);
        return -1;
    }
    tmp = os_realloc(eloop.readers,
            (eloop.reader_count + 1) * sizeof(struct eloop_sock));
    if (tmp == NULL) {
        WSAEventSelect(sock, event, 0);
        WSACloseEvent(event);
        return -1;
    }

    tmp[eloop.reader_count].sock = sock;
    tmp[eloop.reader_count].eloop_data = eloop_data;
    tmp[eloop.reader_count].user_data = user_data;
    tmp[eloop.reader_count].handler = handler;
    tmp[eloop.reader_count].event = event;
    eloop.reader_count++;
    eloop.readers = tmp;
    if (sock > eloop.max_sock)
        eloop.max_sock = sock;
    eloop.reader_table_changed = 1;

    return 0;
}


void eloop_unregister_read_sock(int sock)
{
    size_t i;

    if (eloop.readers == NULL || eloop.reader_count == 0)
        return;

    for (i = 0; i < eloop.reader_count; i++) {
        if (eloop.readers[i].sock == sock)
            break;
    }
    if (i == eloop.reader_count)
        return;

    WSAEventSelect(eloop.readers[i].sock, eloop.readers[i].event, 0);
    WSACloseEvent(eloop.readers[i].event);

    if (i != eloop.reader_count - 1) {
        os_memmove(&eloop.readers[i], &eloop.readers[i + 1],
                (eloop.reader_count - i - 1) *
                sizeof(struct eloop_sock));
    }
    eloop.reader_count--;
    eloop.reader_table_changed = 1;
}


int eloop_register_event(void *event, size_t event_size,
        eloop_event_handler handler,
        void *eloop_data, void *user_data)
{
    struct eloop_event *tmp;
    HANDLE h = event;

    if (event_size != sizeof(HANDLE) || h == INVALID_HANDLE_VALUE)
        return -1;

    if (eloop_prepare_handles())
        return -1;

    tmp = os_realloc(eloop.events,
            (eloop.event_count + 1) * sizeof(struct eloop_event));
    if (tmp == NULL)
        return -1;

    tmp[eloop.event_count].eloop_data = eloop_data;
    tmp[eloop.event_count].user_data = user_data;
    tmp[eloop.event_count].handler = handler;
    tmp[eloop.event_count].event = h;
    eloop.event_count++;
    eloop.events = tmp;

    return 0;
}


void eloop_unregister_event(void *event, size_t event_size)
{
    size_t i;
    HANDLE h = event;

    if (eloop.events == NULL || eloop.event_count == 0 ||
            event_size != sizeof(HANDLE))
        return;

    for (i = 0; i < eloop.event_count; i++) {
        if (eloop.events[i].event == h)
            break;
    }
    if (i == eloop.event_count)
        return;

    if (i != eloop.event_count - 1) {
        os_memmove(&eloop.events[i], &eloop.events[i + 1],
                (eloop.event_count - i - 1) *
                sizeof(struct eloop_event));
    }
    eloop.event_count--;
}


int eloop_register_timeout(unsigned int secs, unsigned int usecs,
        eloop_timeout_handler handler,
        void *eloop_data, void *user_data)
{
    struct eloop_timeout *timeout, *tmp, *prev;

    timeout = os_malloc(sizeof(*timeout));
    if (timeout == NULL)
        return -1;
    os_get_time(&timeout->time);
    timeout->time.sec += secs;
    timeout->time.usec += usecs;
    while (timeout->time.usec >= 1000000) {
        timeout->time.sec++;
        timeout->time.usec -= 1000000;
    }
    timeout->eloop_data = eloop_data;
    timeout->user_data = user_data;
    timeout->handler = handler;
    timeout->next = NULL;

    if (eloop.timeout == NULL) {
        eloop.timeout = timeout;
        return 0;
    }

    prev = NULL;
    tmp = eloop.timeout;
    while (tmp != NULL) {
        if (os_time_before(&timeout->time, &tmp->time))
            break;
        prev = tmp;
        tmp = tmp->next;
    }

    if (prev == NULL) {
        timeout->next = eloop.timeout;
        eloop.timeout = timeout;
    } else {
        timeout->next = prev->next;
        prev->next = timeout;
    }

    return 0;
}


int eloop_cancel_timeout(eloop_timeout_handler handler,
        void *eloop_data, void *user_data)
{
    struct eloop_timeout *timeout, *prev, *next;
    int removed = 0;

    prev = NULL;
    timeout = eloop.timeout;
    while (timeout != NULL) {
        next = timeout->next;

        if (timeout->handler == handler &&
                (timeout->eloop_data == eloop_data ||
                 eloop_data == ELOOP_ALL_CTX) &&
                (timeout->user_data == user_data ||
                 user_data == ELOOP_ALL_CTX)) {
            if (prev == NULL)
                eloop.timeout = next;
            else
                prev->next = next;
            os_free(timeout);
            removed++;
        } else
            prev = timeout;

        timeout = next;
    }

    return removed;
}


int eloop_is_timeout_registered(eloop_timeout_handler handler,
        void *eloop_data, void *user_data)
{
    struct eloop_timeout *tmp;

    tmp = eloop.timeout;
    while (tmp != NULL) {
        if (tmp->handler == handler &&
                tmp->eloop_data == eloop_data &&
                tmp->user_data == user_data)
            return 1;

        tmp = tmp->next;
    }

    return 0;
}


/* TODO: replace with suitable signal handler */
#if 0
static void eloop_handle_signal(int sig)
{
    int i;

    eloop.signaled++;
    for (i = 0; i < eloop.signal_count; i++) {
        if (eloop.signals[i].sig == sig) {
            eloop.signals[i].signaled++;
            break;
        }
    }
}
#endif


static void eloop_process_pending_signals(void)
{
    int i;

    if (eloop.signaled == 0)
        return;
    eloop.signaled = 0;

    if (eloop.pending_terminate) {
        eloop.pending_terminate = 0;
    }

    for (i = 0; i < eloop.signal_count; i++) {
        if (eloop.signals[i].signaled) {
            eloop.signals[i].signaled = 0;
            eloop.signals[i].handler(eloop.signals[i].sig,
                    eloop.signals[i].user_data);
        }
    }

    if (eloop.term_signal.signaled) {
        eloop.term_signal.signaled = 0;
        eloop.term_signal.handler(eloop.term_signal.sig,
                eloop.term_signal.user_data);
    }
}


int eloop_register_signal(int sig, eloop_signal_handler handler,
        void *user_data)
{
    struct eloop_signal *tmp;

    tmp = os_realloc(eloop.signals,
            (eloop.signal_count + 1) *
            sizeof(struct eloop_signal));
    if (tmp == NULL)
        return -1;

    tmp[eloop.signal_count].sig = sig;
    tmp[eloop.signal_count].user_data = user_data;
    tmp[eloop.signal_count].handler = handler;
    tmp[eloop.signal_count].signaled = 0;
    eloop.signal_count++;
    eloop.signals = tmp;

    /* TODO: register signal handler */

    return 0;
}


#ifndef _WIN32_WCE
static BOOL eloop_handle_console_ctrl(DWORD type)
{
    switch (type) {
        case CTRL_C_EVENT:
        case CTRL_BREAK_EVENT:
            eloop.signaled++;
            eloop.term_signal.signaled++;
            SetEvent(eloop.term_event);
            return TRUE;
        default:
            return FALSE;
    }
}
#endif /* _WIN32_WCE */


int eloop_register_signal_terminate(eloop_signal_handler handler,
        void *user_data)
{
#ifndef _WIN32_WCE
    if (SetConsoleCtrlHandler((PHANDLER_ROUTINE) eloop_handle_console_ctrl,
                TRUE) == 0) {
        printf("SetConsoleCtrlHandler() failed: %d\n",
                (int) GetLastError());
        return -1;
    }
#endif /* _WIN32_WCE */

    eloop.term_signal.handler = handler;
    eloop.term_signal.user_data = user_data;

    return 0;
}


int eloop_register_signal_reconfig(eloop_signal_handler handler,
        void *user_data)
{
    /* TODO */
    return 0;
}


void eloop_run(void)
{
    struct os_time tv, now;
    DWORD count, ret, timeout, err;
    size_t i;

    while (!eloop.terminate &&
            (eloop.timeout || eloop.reader_count > 0 ||
             eloop.event_count > 0)) {
        tv.sec = tv.usec = 0;
        if (eloop.timeout) {
            os_get_time(&now);
            if (os_time_before(&now, &eloop.timeout->time))
                os_time_sub(&eloop.timeout->time, &now, &tv);
        }

        count = 0;
        for (i = 0; i < eloop.event_count; i++)
            eloop.handles[count++] = eloop.events[i].event;

        for (i = 0; i < eloop.reader_count; i++)
            eloop.handles[count++] = eloop.readers[i].event;

        if (eloop.term_event)
            eloop.handles[count++] = eloop.term_event;

        if (eloop.timeout)
            timeout = tv.sec * 1000 + tv.usec / 1000;
        else
            timeout = INFINITE;

        if (count > MAXIMUM_WAIT_OBJECTS) {
            printf("WaitForMultipleObjects: Too many events: "
                    "%d > %d (ignoring extra events)\n",
                    (int) count, MAXIMUM_WAIT_OBJECTS);
            count = MAXIMUM_WAIT_OBJECTS;
        }
#ifdef _WIN32_WCE
        ret = WaitForMultipleObjects(count, eloop.handles, FALSE,
                timeout);
#else /* _WIN32_WCE */
        ret = WaitForMultipleObjectsEx(count, eloop.handles, FALSE,
                timeout, TRUE);
#endif /* _WIN32_WCE */
        err = GetLastError();

        eloop_process_pending_signals();

        /* check if some registered timeouts have occurred */
        if (eloop.timeout) {
            struct eloop_timeout *tmp;

            os_get_time(&now);
            if (!os_time_before(&now, &eloop.timeout->time)) {
                tmp = eloop.timeout;
                eloop.timeout = eloop.timeout->next;
                tmp->handler(tmp->eloop_data,
                        tmp->user_data);
                os_free(tmp);
            }

        }

        if (ret == WAIT_FAILED) {
            printf("WaitForMultipleObjects(count=%d) failed: %d\n",
                    (int) count, (int) err);
            os_sleep(1, 0);
            continue;
        }

#ifndef _WIN32_WCE
        if (ret == WAIT_IO_COMPLETION)
            continue;
#endif /* _WIN32_WCE */

        if (ret == WAIT_TIMEOUT)
            continue;

        while (ret >= WAIT_OBJECT_0 &&
                ret < WAIT_OBJECT_0 + eloop.event_count) {
            eloop.events[ret].handler(
                    eloop.events[ret].eloop_data,
                    eloop.events[ret].user_data);
            ret = WaitForMultipleObjects(eloop.event_count,
                    eloop.handles, FALSE, 0);
        }

        eloop.reader_table_changed = 0;
        for (i = 0; i < eloop.reader_count; i++) {
            WSANETWORKEVENTS events;
            if (WSAEnumNetworkEvents(eloop.readers[i].sock,
                        eloop.readers[i].event,
                        &events) == 0 &&
                    (events.lNetworkEvents & FD_READ)) {
                eloop.readers[i].handler(
                        eloop.readers[i].sock,
                        eloop.readers[i].eloop_data,
                        eloop.readers[i].user_data);
                if (eloop.reader_table_changed)
                    break;
            }
        }
    }
}


void eloop_terminate(void)
{
    eloop.terminate = 1;
    SetEvent(eloop.term_event);
}


void eloop_destroy(void)
{
    struct eloop_timeout *timeout, *prev;

    timeout = eloop.timeout;
    while (timeout != NULL) {
        prev = timeout;
        timeout = timeout->next;
        os_free(prev);
    }
    os_free(eloop.readers);
    os_free(eloop.signals);
    if (eloop.term_event)
        CloseHandle(eloop.term_event);
    os_free(eloop.handles);
    eloop.handles = NULL;
    os_free(eloop.events);
    eloop.events = NULL;
}


int eloop_terminated(void)
{
    return eloop.terminate;
}


void eloop_wait_for_read_sock(int sock)
{
    WSAEVENT event;

    event = WSACreateEvent();
    if (event == WSA_INVALID_EVENT) {
        printf("WSACreateEvent() failed: %d\n", WSAGetLastError());
        return;
    }

    if (WSAEventSelect(sock, event, FD_READ)) {
        printf("WSAEventSelect() failed: %d\n", WSAGetLastError());
        WSACloseEvent(event);
        return ;
    }

    WaitForSingleObject(event, INFINITE);
    WSAEventSelect(sock, event, 0);
    WSACloseEvent(event);
}
